The Pentagon said yesterday that Defense Department investigators have found no evidence to support allegations by a GOP congressman and others that a secret program had identified lead hijacker Mohamed Atta more than a year before the Sept. 11, 2001, attacks.

The findings by the Pentagon further challenge assertions by Rep. Curt Weldon (R-Pa.) and two military officers that a small data analysis program called "Able Danger" had identified Atta and three other hijackers as early as 1999, but that Defense Department lawyers prevented the information from being shared with the FBI.

"While we continue to review the documentation and conduct interviews, and while there are some who allege specific documents exist, the Defense Department has not discovered any documentation that shows Mohamed Atta connected to al Qaeda prior to the attacks of 9/11," Pentagon spokesman Bryan Whitman said.

The allegations surrounding Able Danger were first made by Weldon in a little-noticed paragraph in his recent book, "Countdown to Terror," which focuses primarily on assertions about Iran that U.S. intelligence officials have dismissed as fabrications. But the story took off two weeks ago with several prominent news accounts that relied on Weldon and Army Reserve Lt. Col. Anthony Shaffer, and led to internal reviews by the Pentagon and the Sept. 11 commission.

Yesterday, Fox News broadcast a statement from the second officer, Navy Capt. Scott Phillpott, contending that Atta was identified in the first two months of 2000. "My story has remained consistent," he said in the statement.

Shaffer, whose security clearance has been suspended since March 2004, acknowledged last week that his central allegation -- the identification of Atta -- was based on other people's recollections rather than his own. In the accounts given by Shaffer and Weldon, other details have varied.

Shaffer's attorney, Mark S. Zaid, criticized the remarks by Whitman and other defense officials yesterday.

"The Pentagon's public relations campaign to discredit Mr. Shaffer simply reveals that it is looking for documents in the wrong places and talking to the wrong people," Zaid said.

But a Pentagon official, who spoke only on the condition of anonymity because of the ongoing probe, said the investigation "has been both broad and deep" and has included interviews with those involved in Able Danger.

In July 2004, the Sept. 11 commission interviewed Phillpott, who told investigators that he had briefly seen Atta's name and photograph on an Able Danger chart between February and April 2000, according to a commission account. Shaffer has since said that Phillpott's recollection formed the basis of his allegations.

But the Sept. 11 panel said it did not find Phillpott's assertions credible because there were no documents to support them, and because Atta did not first travel to the United States until June 2000. The commission has also dismissed Shaffer's assertion that he mentioned an early identification of Atta to commission staffers during a 2003 meeting in Afghanistan.

Thomas H. Kean, chairman of the now-disbanded Sept. 11 commission, called on the Bush administration yesterday to provide more information about what it knows regarding Able Danger and the Atta allegations.

Kean focused specifically on an assertion in Weldon's book about Stephen J. Hadley, then deputy director of the National Security Council. Weldon wrote that shortly after the Sept. 11 attacks, he gave Hadley a 1999 Able Danger chart that "diagrammed the affiliations of al Qaeda and showed Mohammed [sic] Atta and the infamous Brooklyn Cell." Weldon repeated the allegation last week.

"At some point, somebody has to say this is true or this is not true," Kean said. "He's supposed to have a list of names of terrorists in his possession. He either does or he doesn't. . . . It's a very significant question."

The NSC press office has repeatedly declined to comment, referring questions to the Pentagon.

Rep. Curt Weldon (R-Pa.) asserted that hijacker Mohamed Atta had been identified by 1999.